A major obstacle to long-term control and cure of HIV has been the persistence of HIV in reservoirs that contain latently infected, resting, and productively infected CD4+ T cells. The recent cure of a patient with HIV by hematopoietic cell transplantation (HCT) with HIV-resistant cells has demonstrated the enormous potential of this strategy. Unfortunately, HIV-resistant donors are extremely rare, severely limiting this approach. Here we propose a multi-investigator program to study the biology of the HIV reservoir in patients and nonhuman primates, and to develop novel strategies to repopulate the hematopoietic system with HIV-resistant cells. We have assembled a team consisting of leaders in the fields of HIV, genetic modification, translational research, and transplantation. Specifically, we will combine autologous HCT with genetic modification approaches, allowing us to disrupt the CCR5 receptor in autologous stem cells, and also destroy the integrated HIV provirus contained within those cells. We propose 5 highly integrated projects in pursuit of our overall goal, and 5 cores for their support. Project 1, Hematopoietic Cell Transplant: Platform for Purging the Latent HIV Reservoir (Ann Woolfrey, FHCRC), will seek to clarify the relative contributions of the preparative regimen and the donor graft required for purging the latent HIV reservoir. Project 2, ZFN-Modified Stem Cells for HIV Eradication (Philip Gregory, Sangamo Biosciences), will seek to endow the transplant recipient's own cells with stable resistance to infection, via zinc finger nuclease disruption of the CCR5 locus. Project 3, CCR5 Targeting to Control HIV/SHIV in Nonhuman Primates (Hans-Peter Kiem, FHCRC), will use a non-human primate model of HIV/SHIV infection to determine whether genetic modification of the CCR5 locus and HCT can provide long-term control of HIV. Project 4, Targeted Disruption of Integrated SHIV by Engineered Homing Endonucleases, (Keith Jerome, FHCRC), will seek to directly address the problem of viral persistence, by designing highly specific homing endonucleases that can recognize and mutate integrated SHIV provirus in infected macaque hematopoietic cells. Project 5, Aptamer and Dendrimer Delivery of Zn Finger Nuclease and Homing Endonuclease mRNA and cDNA (John Rossi, Beckman Research Institute of the City of Hope), will develop and optimize delivery strategies by which ZFNs and HEs can be delivered to their target cells. Given our leading roles in Transplantation and HIV research, we believe we are uniquely positioned to move these concepts from a highly relevant nonhuman primate HIV/SHIV model toward a cure for HIV-infected patients.